Dobby for shuttleless automatic looms



April 6, 1954 v.v WERNER ET AL 2,674,272

DOBBY FOR SHUTT'LELESS AUTOMATIC' LOOMS Filed May 23, 1950 3 Sheets-Sheet 1 INVENTOR. l//LEM WEKA/ER 8f AGT April 6, 1954 vQ WERNER' ETAL 2,674,272

'DOBBY FOR SHUTTLELESSS Au'ron/r/vrrc Looms Filed May 23, 1950 3 Sheets-Sheet 2 IN V EN TOR.

V/LEM WERNER@ KAREL KUBE L KA AGT April 6, 1954 v. WERNER ET AL 2,574,272

DOBBY FOR SHUTTLELESS AUTOMATIC LooMs Filed May 23, 1950 :5 Sheets-sheet 5 IN VEN TOR. www WMA/ER @C Y 1mm Ku/.fum

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AGT

Patented Apr. 6, 1954 UNITED STATES ,.i'lNT OFFICE Vilm Werner, Plzen,

Blansko, Czechoslovakia, assignors to Prototypa, Narodni Podnik, a corporation of Czecho- Slovakia and Karel Kubelka,

Application May 23, 1950, Serial No. 163,754

Claims priority, application Czechoslovakia May 31, 1949 9 Claims. (Cl. 139-57) The present invention relates to mechanisms for actuating the harnesses of Weaving looms, and is particularly directed to a dobby for association with an automatic shuttleless loom.

The dobbies heretofore employed for operating loom harnesses usually include harness levers to which the several harnesses of the associated loom are suitably connected. Knives are mounted in guides on the dobby frame for reciprocating movement and are connected to a rocker to be actuated by oscillation of the latter. In order to provide a connection between the knives and the harness levers only during predetermined intervals in the operating cycle or the loom, hooks are connected to the harness levers and engageable with the knives, with dobby lingers being arranged to move the hooks into and out oi engagement with the reciprocating knives, The dobby fingers are in turn actuated by pegs carried by a harness chain which is suitably driven from the crank-shaft of the loom. In one form of dobby, the rocker is oscillated by a connect ing rod which extends between a rocker arm on the rocker and a dobby crank-shaft or driving shaft which is driven through a gear transmisii sion from the main crank-shaft of the loom. In another form of dobby, the rocker thereof is driven from a non-circular radial cam or a disc having a non-circular cam groove therein and mounted upon the driving shaft of the A dobby. In another mechanism for effecting the interrupted movements of the loom harnesses, gears are provided with cables or flexible members connected eccentrically thereto and attached directly to the harness frames.

teeth ci segment gears arranged on a suitably rotated cylinder. vWhile the mechanisms men# tioned above operate to eect interrupted movements of the harnesses, the structures thereof are complex and inaccessible for the purposes oi repair and adjustment. Further, in operation, such mechanisms require the engagement of relatively stationary parts with parts moving at high speeds thereby producing severe shocks which increase the noise of operation, vibration and wear on the parts. For example, in the dobbies described above, the hooks operated by the (lobby lingers are moved into engagement with the knives which travel at substantial speeds. At the instant or such engagement, the hooks and the associated harness levers are at rest, at least in the direction of movement of the knives, and severe stresses will be developed as the knives first strike against and then accelerate the hooks The gears are 7, driven intermittently by engagement with the and harness levers. The resultant vibration and impact causes considerable losses in energy. Further, Where the rocker of the dobby is driven from eccentrically mounted discs or grooved discs, as mentioned above, the latter Will give rise to substantial unbalanced forces to produce excessive vibration, Wear and noise unless extreme preciseness is exercised in their manuacture.

Accordingly, an object of the present invention is to provide a dobby for a shuttleless automatic loom which avoids al1 of the above disadvantages of the devices heretofore in use.

Another object is to provide a dobby having a rocker driven by an eccentric device which is arranged so that during a predetermined angular movement of the dobby crank-shaft the rocker and associated knives remain at rest, with the coupling and unccupling of the various harness driving systems relative to the knives occurring whilethe knives are thus at rest, thereby avoiding the shocks, vibration and noise previously associated with such coupling and uncoupling.

A further object of the present invention is to provide a dobby of the described character wherein the knives are reciprocated in opposite directions and are held at rest for a predetermined period during each reciprocating cycle thereof in positions at the adjacent ends of their strokes for selective engagement during that period with one or the other of two coupling members included in each harness driving system so that at the end of the rest period the harnesses associated With said systems are either raised or 10W- ered by connection to one or the other of the reciprocating knives.

In accordance with the present invention the foregoing objects, and other objects, features and advantages appearing hereinbelow, are achieved by providing a dobby which includes a rocker, a connecting rod attached at one end toi the rocker and driven by a rotating eccentric mechanism arranged to cause the other end of the rod to follow a substantially cardioid path so that the rocker is maintained at rest during a predetermined period or interval in each revolution of the eccentric mechanism. TWO knives are connected to the rocker for reciprocating movements in opposite directions and are arranged to be disposed at adjacent ends of their paths of travel during the rest period of the rocker. A harness driving system is provided in the dobby for each harness on the associated loom and includes a linearly movable slide member guided along a path parallel to the paths of movement of the knives and connected to harness levers to swing the latter, and

a hook assembly mounted on the linearly movable slide member for actuation laterally relative to the paths of movement of the knives. Each hook assembly is constructed so that, when the knives are disposed at said adjacent ends of their paths of travel, the hook assembly is engageable With one or the other of the knives depending upon the direction of the lateralactuation of the hook assembly. Thus, when the knives are moved in opposite directions from their rest positions, each linearly movable slide member is carried along by the knife with which its hookassembly is engaged to raise or lower the related harness. Finally, the lateral actuation of the hook assemblies is produced by suitable link systems driven by a conventional harness chain which is operated in synchronism with the dobby to cause movements of the hook assemblies only during the periods when the knives are at rest.

In order to provide a better understanding of the invention, a preferred embodiment thereof is described Ahereinbelow and shown in thefaccompanying drawings, wherein:

lFig. 1 is a diagrammatic illustration of a'dobby embodying the present invention in association with the relatedparts of an automatic loom;

Fig. `2 is a side elevational view of a driving mechanism for the dobby of Fig. l

Fig. 3 isa top plan view, partly broken away and in section, of the driving mechanism of Fig. 2;

Fig. 4 is a diagrammatic View of the elements of thedobby of Fig. 1 in the positions occupied thereby during the .period of rest of the dobby rocker;

Fig. 5 is a view similar to Fig. 4, but showing the positions of the elements inmoving the associated harness in onedirection; and

Fig. 6 is a view similar to Fig. 5, but showing `the positions of the elements in moving the associated harness in the other direction.

Referring to the rdrawings in detail, and initially 'to Fig.1 thereof, a dobby embodying the present invention is there shown diagrammatically in association with portions of a conventional automatic loom. The loom includes a frame which supports the conventional main crank-shaft for actuating the lay (not shown). The dobby includes a dobby driving shaft I which is driven, through a suitable gear transmission,

by the main crankshaft of the loom. A crank 4 (Figs. '2 and 3) is rotatably mounted within a dobby housing 46 for rotation about an axis 91 and has a bevel gear 3 xed thereto and meshing with a suitable bevel gear 2 on the dobby driving shaft I. The crank 4 carries acrank pin 5 adjacent its outer end, and an eccentric bushing 6 is rotatably mounted on pin 5 for rotation about the axis 92 of the latter. The bushing 5 has its center located at 03, that is, displaced relative to its axis of rotation, and has a spur gear 'I xed thereto coaxial relative to its axis of rotation 02. A gear 8 is fixedly mounted within the dobby housing in a position coaxial relative to the axis of rotation 01 of the crank@ and meshing with the gear 'I on the eccentric bushing 5. Thus, as the crank 4 is` rotated by its connection to the main crankshaft of the loom, the gear 'i rolls on the gear 8, so that the eccentric is rotated about the axis 92, as well as being turned with the crank about the axis ci of the latter.

The gears I and 8 are proportioned so that the center E23 of the eccentric bushing 6 will follow a path K which represents the transition of a cardioid into a circle having the radius of ,crank 4, that is, the distance between 01 and 02. A connecting rod 9 is mounted at one end on the eccentric bushing 6 so that that end of the connecting rod will follow the cardioidal path described by the center S3 of the bushing. The opposite end of connecting rod 9 is mounted on a pivot or pin I0 carried by a rocker arm II extending from a rocker I2 whichis pivotally mounted at its center on a pivot I3 within the dobby housing. The connecting rod 9 has a length, between the center Us and the axis of .pin I9, which is substantially equal to the radiusof curvature of the concaved portion of the pathK, that is, the portion of the path K described by the center E3 of the eccentric bushing B during rotation of the crank li through the angular distance dened by the angle a. Thus, during movement of crank l through the angular distance a, the rocker arm II will remain at rest in the position shown in Fig. 2, and during the remainder of the rotation of crank 4, the rocker arm I I will be oscillated between its position in Figs. 2 and ll and its position in Figs. 5 and 6. It will be noted in Fig. 2, that the angular distance ais symmetrical with respect to the position of the radial medial line of crank 4 when that medial line is aligned with the center Us of the eccentric bushing and the center of connecting pin` I0.

Continuing with the structure of the dobby embodying the present invention, it will be seen in Fig. 2 that links Id and I5 are pivotally connected to the opposite ends of the rocker I 2 by pivots I6 and Il, respectively. The links I4 andv I5 are attached to knives I6) and I 8, respectively (Figs. 4, 5 and 6), which are suitably guided within the dobby housing to follow linear vpaths of reciprocation. The links I4 and I5 are dimensioned so that, with the rocker in its position of Figs. 2 and 4, the knives I8 and I 9 will be disposed relatively close together, while oscillation of the rocker I2 to the'position shown in either of Figs. 5 and 6 will cause downward movement of the knife I9 and upward movement of the knife I8. Since the rocker arm II is maintained at rest, in the position of Fig. 4, for a predetermined period in the manner described above, it is apparent that the knives I8 and I9 will also remain at rest in their close together positions (Fig. 4) for that same predetermined period.

In order to transmit the movements of knives I8 and I9 tothe various harnesses of the associated loom, the dobby embodying the present invention is'provided with a harness driving system for each of the harnesses. Each harness driving system includes a slide member 2U formed with longitudinal slots 24 and 25 opening at its opposite ends to receive guide rods 22 and 23, respectively, which limit the movements of the slide members 20 to linear paths parallel to the paths of movement of the knives I8 and I9. The side edges of each slide member 20, adjacent the end having the slot 24 formed therein, are provided with gear racks 2`I which mesh with gear segments 28 and 29 formed on the inner ends of paired harness levers 2I. The levers 2| extend in opposite directions from the related slide member 20 and are pivoted intermediate their lengths, as at 30, upon the dobby housing. The outer ends of each pair of harness levers 2I are pivotally connected, as at 3I, with rods 32 which pivotally attach, as at 33, to the related harness 34 vof the loom. The frames of the harnesses 34 are preferably slidable in suitable Vvertical guides 35 `carried by the loom frame, vand in the illustrated arrangement, each harness will be raised and lowered as the related slide member is lowered and raised, respectively, from the position thereof shown in Fig. 4.

In order to provide for the selective coupling of each slide member 20 with either the knife I8 or the knife I9, the slide member 2G is formed with a lateral projection 26 extending from the end portion of the slide member having the slot formed therein. The lateral projection 25, as can be seen in Figs. 4, 5 and 6, extends between the knives I8 and I9, and the links i4 and I5 are dimensioned so that the knives land I9 contact the projections 25, above and below the latter, when the knives are in their rest positions (Fig. 4). A hook assembly 33 slidably mounted on each projection 26 for movement laterally relative to the knives I and I9. The hook assembly 3S preferably includes tubular end parts linked together by a connecting web and slidably receiving the projection Zi. The tubular end parts of the hook assembly are formed with oppositely directed arms 37 and 38 extending substantially at right angles to the axis of the projection 26. The arms 31 and 38, at their free ends, are provided with hook formations 39 and `4Q, respectively, extending toward each other. Each of the hook formations 35 and 4i) is spaced from the adjacent edge of the projection 26 by a distance sufficient to define a space adequate to receive the knife lf3 or the knife I9, respectively. Further, the arms 31 and 33 are spaced apart in the direction of sliding movement of the assembly 35 by a distance sumcient to ensure that, when one of the hook formations 39 and 4i? is engaged with the J.

to the left (as viewed in the drawings) during the period when the knives I3 and I 9 are at rest, the hook formation engages the knife It, while the hook formation 39 is moved away from the knife I8. After such engagement has been effected, the knives I8 and I9 move apart, as in .t

Fig. 5, and the knife I9, by reason of its engagement with the hook assembly 35, carries the slide member 2li in the downward direction, thereby elevating the related harness of the loom. As the knives are returned to their rest :I

positions by the links I4 and I5 which govern the movement of the knives positively, the knife I9 will press against the lower edge of the projection 25 to return the slide member 2e upwardly to its original or neutral position, On

the other hand, when the hook assembly 36 is displaced to the right, as viewed in the drawings, during the rest period of the knives, the hook formation 39 engages the knife I8 while the hook formation 40 is moved out of the path of travel of the knife I 9. Therefore, when the knives are subsequently moved apart (Fig. 6), the knife I8 carries the slide member 20 upwardly to effect downward movement of the related harness 34. nal position (Fig. 4) it bears against the upper edge of the projection 25 to move the slide member 20 back to its neutral position.

In order to effect the selective displacement of the hook assemblies 35 to the left and right f (as viewed in the drawings) for coupling the related slide members 20 to the knife Iii or the knife I9, as set forth above, each of the hook assemblies is provided with a tongue 4I extending longitudinally therefrom and carrying a fol- As the knife I3 returns to its origilower 42 which is slidable in an elongated slotted end portion 43 formed on a plunger 44. The plunger 44 is reciprocatable in a bearing 45 carried by the dobby housing for linear movement parallel to the direction of displacement of the related hook assembly and the slotted end portion 43 is disposed at right angles to the plunger 44 so that the follower 42 may move along the slotted end portion of the plunger as the related slide member 2i) is moved up and down. A spring 4l acts against each plunger 44 to yieldably urge the latter toward the left (as viewed in the drawings) and each plunger is periodically moved to the right, against the force of spring 41, by mechanism that includes a link 48 connected at one end to the plunger and at its other end to one arm of a bell-crank 5E rockably mounted on the loom frame. Another link or rod 49 is attached at one end to the other arm of bellcrank 5G and at its other end to a finger or lever 5I which is suitably pivoted on the loom frame, as at 52, and rides upon a conventional dobby control device, for example, a harness chain, which is driven in synchronism with the drive of the knives I8 and I9 so that the control device moves the fingers 5I only during the periods when the knives are at rest, that is, when the crank 4 is moving through the angle a.

Thus, the action of the harness chain upon the fingers 5l and of the springs 4T will determine whether the related slide members 2b are coupled to the knife I8 or the knife i9 during the rest period of the latter, thereby controlling the raising and lowering of the related harnesses. Since the coupling and uncoupling of the slide members 2d and the knives i8 and I9 is effected only when the latter are at rest, such coupling and uncoupling is not attended by shocks, vibration and resultant noise thereby reducing wear on the several parts, as well as annoyance and fatigue to the operator to permit production of cloth of improved o uality. Further, the particular mechanism provided for effecting the interrupted oscillation of the rocker arm il, does not require the use of cams having non-circular perip'heries or grooves which are diicult to produce with a preciseness suicient to provide the desired operation. Further, the described driving mechanism achieves the precise and noiseless automatic operation of the dobby merely by the relationship of the parts and the kinematic rules involved. Preferably, the dobby embodying the present invention is formed as an independent unit which can be re placed as a whole, with all of the parts being enclosed in the housing and run in an oil bath to provide adequate lubrication.

While we have described in detail and illustrated a specific preferred embodiment of the invention, it is to be understood that the invention is not limited to that precise embodiment, and that various changes and modifications, obvious to one skilled in the art, may be effected therein without departing from the scope of the invention which is intended to be dened in the appended claims.

What we claim is:

l. A dobby for operating the harnesses of an associated. loom; said dobby comprising a rotatable driving crank, means for rotating said crank from the shaft of the loom, a rocker mounted intermediate its ends for oscillation, means interposed between said crank and rocker and operative to oscillate the latter while maintaining the rocker at rest for a predetermined 7. period at one extreme oi the oscillating: move,-v ment thereof during the continuous rotation osaid crank, two knives guided for linear'move'- ment, link means extending from said knives to the opposite ends of said rocker for reciprocating said knives in opposite directions as said rocker is oscillated, a slide member for each of the harnesses of the associated loom, means guiding said slide members forlinear movements parallel to said knives, pivotally mounted harness levers associated with each of said slide members, meshing toothed means on said slide members and the associated harness levers for effecting swinging of the latter in response to linear movements of the related slide members, a hook assembly displaceably mounted on each of' said members for selective coupling engagement with one of said knives, and control means connected to each hook assembly for manipulating the latter into coupling engagement with a selected one of said knives during said predetermined period when the rocker is maintained at rest.

2. A dobby according to claim 1; including an oil-tight box containing at least said driving crank and said means interposed. between said crank and rocker.

3. A dobby according to claim 1; wherein said slide members are formed with elongated slots f opening at the opposite ends thereof, and said guide means for the slide members includes guide rods received in said elongated slots.

4. A dobby according to claim 1; wherein said means interposed between the crank and rocker includes an eccentric bushing rotatably mounted on said crank for rotation about an axis parallel to and displaced radially from the axis of rota,- tionof said crank, a gear fixed to said eccentric bushing for rotation coaxially with said axis of rotation of the latter, a iixed gear coaxial with said axis of rotation of said crank and. meshing with said gear fixed to the bushing so that the center of said eccentric bushing will follow a cardioid path during rotation of said crank, a rocker arm extending from said rocker, and a connecting rod rotatably mounted at one end on said eccentric bushing and pivotally connected at its other end to said rocker arm, said rocker arm being at rest during the movement of said crank through an acute angle.

5. A dobby according to claim l; wherein each of said slide members is formed with alateral projection extending between said two knives; each hook assembly including a body slidable on the lateral projection of the related slidemem '5 ber, and oppositeiy directed arms extending from the opposite end portions of each body andv ter-- minating in hook formations directed toward each other and parallel to said projection, said hook formations being formed to alternately engage said knives depending upon the position of said body on said projection; and wherein said control means includes a reciprocatable plunger for each of said hook assemblies extending at right angles to the path of movement of said slide member, an end portion on said plunger having an elongated slot therein parallel to said path of the slide member, a follower on said hook assembly slidably engaging in said elongated slot of the related plunger, spring means acting against said plunger to yieldably urge the latter in the direction for eecting engagement of one of said hook formations with a related one of said knives, andV means' arranged forcontroli'by' a harness chain and operative to urge thefplungers in the opposite-direction againstythe force of said. spring means to effect engagement of the; other of` said hook formations with theV other of said: knives.

6. A dobby according to. claim 1; includingfan; enclosing housing, and a bearing carried by said housing for supporting each of said plungers.

7. A dobby according to claim 1;- wherein said, meshing toothed means includes gear racks exe tending longitudinally onf saidv slide members and gear segments on' said harness levers con.- centric With theaxes of pivotingy of thelatter and meshing with the gear racks on the associated slide members.

8. A dobby for operating-the harnesses ofan. associated loom; said dobby comprising a rota tably driving crank, means forrotatingfsaid crankr from the main shaft of the associated loom,v a .rocker oscillatably mounted ends, means interposed between said drivingv crank and said rocker to oscillate theflatterfand operative to maintain therocker at rest for a predetermined period at one extreme of the movement thereof during the continuous rotation of' said crank, two knives, means connecting said knives to the opposite ends of said rocker so that the knives are reciprocated in: oppositel directions when said rocker isv oscillated, pivotally mounted harness levers for each of the'harnesses of the associated loom, separable means forI operatively couplingthe harness levers for each harness to a selected oneof saidknives, and control; means operative during said period of rest of said rocker to effect coupling and uncoupling of said-separable means and said knives.

9. A dobby according to claim; wherein:` said means interposed,betWeen-the'driving crank and the rocker comprises anl eccentric bushing rotatably mounted on said crank for rotationy relative to the latter about an axis parallel to-and displacedfradiallyv from the axis of rotation of the crank, saidl eccentric bushinghaving'a cylindrical surface the center'ofr which is spaced radi-- ally from said axis of rotation ofv the bushing, a1I gear fixed to said eccentric bushing and arranged coaxially with the axis of rotation of said bushing, a fixed gear arranged coaxially with said: axis of rotation of the crank and meshing with said gear fixed to the bushing so that, as the crank rotates, said center of the bushingl will followv a cardioid path, a rocker arm extendingl from said rocker, and a connecting rod havingl means at one end to receive'said cylindrical surface of the eccentric bushing and pivotally'connected at its other end to said rocker arm, said gears being meshed so that the radially reducedV portion of said cardioidpath is symmetrical with respect tol the radial medial line o said crank when said connecting rod is aligned with thel latter.

References Cited in the file of this patent I UNITED STATES PATENTS Number Name Date 1,892,323 Staubli Dec. 27, 1932'- FOREIGN PATENTS Number Country Date 329,357 Italy Sept. 5, 1935 345,399 Great Britain Mar. 2G, 1931 422,609 Germany Dec. 5, 1925 444,320 France Oct. 15, 1912 intermediatev its; 

